Fats and oils are complex water insoluble substances derived from animal or vegetable sources and comprised of a large number of organic materials. The major components are glyceryl esters of fatty acids, particularly triglyceryl esters derived from lauric, myristic, palmitic, stearic, erucic, oleic, linoleic and linolenic acids. Traditionally, oils are distinguished from fats only in that they are liquid at room temperature, and for convenience, the term `fats` as used hereafter will be assumed to refer equally to oils.
Commercial exploitation of fats is extensive. Millions of tons of fats are directly used per annum in edible products, the most important of which are butter, margarine, lard, shortening, mayonnaise, salad oil and cooking oil. Large quantities of fat are also used directly in non-food products, for example, in grease and lubricants, in cosmetics, and in paints and varnishes (as `drying oils`) In addition, fats are valuable raw materials in the chemicals industry as major sources of fatty acids and their derivatives, among which particular mention should be made of salts, esters, alcohols, amides and other nitrogen derivatives. Manufactured products which commonly incorporate fatty acids or fatty acid derivatives are soaps, plasticisers, polymers, rubber tyres, cosmetics and alkyd resins.
A large proportion of the non-food consumption of fats is accounted for by the production of surface active agents for use as detergents, cleansers and emulsifiers. Among the most important surface active agents are soaps, i.e. salts of fatty acids with sodium, potassium or other metal cations, or with non-metallic cations such as those containing a quadrivalent nitrogen atom. Many other classes of fatty acid-based surface active agents e.g. fat derived surfactants including secondary alkane suphonates, alcohol sulphates, ethoxylated fatty alcohol sulphates, mono and dialkanolamides and alkanolamide sulphates, fatty alcohol ethoxylates, polyethoxylated fatty acid esters, ethoxylated alkanolamides; cationics (particularly quarternary ammonium compounds); amine oxides, ethoxylated derivatives of amine oxides, and amphoterics and sorbitan esters are known and utilised in the synthetic detergent industry.
Glyceride derived emulsifiers are used in the food industry and the present invention relates to them also Examples are mono-/di-glycerides and their esters with lactic acid, citric acid, acetic anhydride and diacetyltartaric acid; stearoyl lactylates; fatty acid esters of sucrose, sorbitol, propylene glycol and polyglycerol; poly (fatty acid) esters of polyglycerol.
A problem feature of many of the above mentioned products arises from the occurrence in fats of materials which are odoriferous and which have the potential to adversely affect products' odor properties, and also, by extension to the edible products area, the perception of taste, since this is influenced by both flavor and odor. The magnitude of the problem is generally difficult to gauge since the occurrence of the odoriferous materials is dependent on many factors such as type of constituent fats, geographical source, chemical and thermal history of the fats, storage conditions, age of product, and presence or absence of preservatives and anti-oxidants. Often, several of these factors may vary simultaneously with the result that odor problems may occur spasmodically and be difficult to rationalize. Furthermore, it is clear the intrinsic odor characteristics of the product itself, and its intended use, will also have a bearing on the required quality of the incorporated fat.
An example of a malodorous material is the unsaturated aldehyde 2,4-decadienal which gives a distinctive green note at sub ppb levels. This aldehyde has been detected in the headspace above deteriorated soya bean oil. Other malodour aldehydes are known to be present in fat derived materials, e.g. 2,4-dodecadienal.